You can either:
- Change the default URL to end with "/#/explore" instead of "/#/projects". I am not sure this applies to all users, though.
- Go to the page where you only see "Top Level Projects". Then click your avatar and select "Make this the start page for all users"
Note that the second option will require people with their own start page to reverse it themselves.
I have the same question. Is it possible for Server Admins to change what shows up by default. We do not want data sets or data roles displaying by default in the Content Type filter.